Pack and frame for pack
A pack which includes a sac, an internal frame for the sac, a shoulder harness and a hip belt; the frame includes a pair of spaced flexible rods positioned one on each side of the frame so as to extend down at least the lower part of the length of each side of the sac; tensioning means are secured between each flexible rod at or adjacent the end of said flexible rod, and an adjacent portion of the hip belt; each said tensioning means being adapted to move the corresponding flexible rod so as to bow and tension said rod and provide a relatively rigid weight transmitting connection between said rod and the corresponding portion of the hip belt; the arrangement being such that said movement of said flexible rods tends to lift the frame and the pack, decreasing the loading on the shoulder harness and increasing the loading on the belt.
The present invention relates to improvements in climber's or tramper's packs, and to frames for such packs.
BACKGROUND ARTA modern pack consists of a sac in which equipment may be carried, the sac being mounted on a frame, and a shoulder harness secured to the sac or to the frame. Since carrying a heavy load supported only from the shoulders can lead to backache or even to back damage, a majority of modern packs also include a hip belt which is connected to the sac or the frame, generally at or close to the base of the sac, to transfer some of the load from the shoulders to the hips.
Although using a hip belt reduces the strain on the back, the belt itself can cause problems to the wearer, due to the way in which the human body moves when walking.
When a human being walks, he leans backwards and forwards with each step (
Also, when a human being bends or steps up, his back extends:—the further the person leans forwards, the longer his back becomes. This extension of the back is in a curved plane, following the natural curve of the back.
Because of the above described movements, a hip belt which is rigidly secured to the pack, and which therefore moves with the pack, is very uncomfortable for the wearer, because the hip belt is constantly rubbing against the wearer due to the relative movements of different parts of the wearer's body when walking. The hip belt cannot be loosened to prevent this rubbing, because the belt must fit snugly to transmit load to the wearer's pelvic girdle and relieve the load on his back.
The above described problem was partially solved by the pivotal hip belt connection provided by New Zealand Patent No. 201751 (Macpac Wildemess Equipment Limited) dated 25th Jul. 1983.
However, the hip belt described in New Zealand patent No. 201751 was not a complete solution to the problem:—because the hip belt was secured to the pack by a comparatively narrow connection, the load transfer from the pack to the hip belt was concentrated at the connection point and was distributed around the pelvic girdle of the wearer only by the stiffness of the hip belt. The more rigid the hip belt, the better the load transfer, but in general, the more rigid a hip belt is, the less comfortable it is to wear. Thus, the problem remained of providing a harness which permitted relative movement between the wearer's back and hips in at least three directions but which provided an efficient load transfer around the pelvic girdle of the wearer without resorting to the use of an uncomfortably stiff hip belt.
New Zealand Patent 335931 provides a frame and hip belt which give excellent weight transfer, but both the frame and the hip belt are bulky and thus comparatively heavy to wear, and are relatively expensive to manufacture.
PCT Application PCT/US97/13396 discloses a backpack frame which also is designed to overcome the problem of efficient weight transfer; this frame consists of an elastomeric pad combined with a pair of spaced resilient rods which extend down the back of the pad and which can be flexed to a greater or lesser extent by tightening or slackening the hip belt of the pack. However, the degree of fixing of the resilient rods, and hence the amount of load transfer to the hip belt, depends upon the tightness of the hip belt:—there is no provision for altering the amount of load transfer independent of the tightness of the hip belt. In practice, it is often desirable to be able to alter the amount of load transfer to the hip belt without actually tightening the hip belt. Further, increased flexing of the resilient rods tends to pull the pack load closer to the user's back, but does not necessarily lift part of the load from the shoulder harness.
DISCLOSURE OF INVENTIONIt is an object of the present invention to provide a pack and a pack frame which are comparatively lightweight and thus simpler from a user's perspective, whilst also providing efficient and easily altered weight transfer from the pack to the hip belt.
The present invention provides a pack which includes a sac, an internal frame for the sac, a shoulder harness and a hip belt;
wherein the frame includes a pair of spaced flexible rods positioned one on each side of the frame so as to extend down at least the lower part of the length of each side of the sac;
and wherein tensioning means are secured between each flexible rod at or adjacent the end of said flexible rod, and an adjacent portion of the hip belt; each said tensioning means being adapted to move the corresponding flexible rod so as to bow and tension said rod and provide a relatively rigid weight transmitting connection between said rod and the corresponding portion of the hip belt; the arrangement being such that said movement of said flexible rods tends to lift the frame and the pack, decreasing the loading on the shoulder harness and increasing the loading on the belt.
BRIEF DESCRIPTION OF DRAWINGSA preferred embodiment of the present invention is described in detail with reference to the accompanying drawings, in which:—
Referring in particular to
Referring in particular to
The outer leg 10a, 11a of each U-shaped portion is connected to a flexible rod 13,14, the longitudinal axis of which is aligned with the longitudinal axis of the corresponding leg.
The inner leg 10b, 11b of each U-shaped portion is formed integrally with a looped portion 15 which supports the lower portion of the sac and lies between the flexible rods 13,14.
The outer and inner legs 10a/b, 11a/b are tied together adjacent their lower ends by crossbars 10c, 11c.
As shown in
The frame 5 is secured inside the sac 3 in known manner, as shown in
The sac 3 is of known design apart from the addition of a fabric wing at each lower rear corner of the sac. Each wing 4 is roughly triangular in shape, and includes two parallel pieces of fabric with padding sandwiched between them.
As shown more detail in
Two parallel openings 16,17 into the Interior of each wing 4 are formed in the outer edge 4 c (.e. furthest from the edge 4a), adjacent the lower edge 4b.
Each opening 16, which is closest to the edge 4c, receives one end 18 of the hip belt 8; the end 18 passes through the width of the wing 4 and is sewn to the sac adjacent the opening 16.
Each opening 17 receives an adjustment strap 19 which extends through the opening 17 and is secured at its inner end to the corresponding flexible rod 13,14 adjacent the lower end of the rod. Each strap 19 is secured to the corresponding flexible rod 13,14 by means of a retainer 20 formed integrally with the rod. The outer end 21 of each adjustment strap 19 passes through a buckle 22 which is secured to the hip belt 8. For reasons of clarity, the buckle 22 is shown in
The above described pack is used as follows:—the pack is positioned on the wearer's shoulders in the usual way, and the hip belt is buckled around the wearer's hips. In the untensioned position shown in
To increase the proportion of the weight of the pack which is transferred from the frame to the hip belt, the wearer pulls the straps 19 in the direction of Arrow A, pulling the flexible rods 13,14 in the direction of Arrow B. The adjustment buckles 22 hold the straps 19 in the bowed, i.e. tensioned, position, retaining the flexible rods 13,14 in the position shown in hatch lines (14a in
The pack of the present invention is capable of providing efficient weight transfer to the hip belt, but is substantially simpler to manufacture and lighter in weight than comparable designs.
Claims
1. A pack which includes a sac, an internal frame for the sac, a shoulder harness and a hip belt;
- wherein the frame includes a pair of spaced flexible rods positioned one on each side of the frame so as to extend down at least the lower part of the length of each side of the sac;
- and wherein tensioning means are secured between each flexible rod at or adjacent the end of said flexible rod, and an adjacent portion of the hip belt; each said tensioning means being adapted to move the corresponding flexible rod so as to bow and tension said rod and provide a relatively rigid weight transmitting connection between said rod and the corresponding portion of the hip belt; the arrangement being such that said movement of said flexible rods tends to lift the frame and the pack, decreasing the loading on the shoulder harness and increasing the loading on the belt.
2. The pack as claimed in claim 1, wherein said frame is a skeleton frame made of rod or bar.
3. The pack as claimed in claim 2, wherein the frame consists of a pair of spaced U-shaped portions inclined at an acute angle to each other and secured together, and spaced apart, by one or more crossbars, the inner legs of said U-shaped portions being secured together by a looped portion, and the outer leg of each U-shaped portion being secured to one of said flexible rods.
4. The pack as claimed in any one of the preceding claims, wherein each tensioning means comprises a strap secured at or adjacent the end of the corresponding flexible rod, the other end of said strap extending through an adjustment buckle.
5. The pack as claimed in claim 4, wherein the end of each flexible rod lies within a wing formed upon the lower side portion of the sac.
6. The pack as claimed in claim 1 or claim 3, wherein the end of each flexible rod lies within the hip belt.
Type: Application
Filed: Jul 15, 2004
Publication Date: Aug 31, 2006
Applicant: MAPAC Wilderness Equipment Limited (Christchurch)
Inventors: John Goulding (British Columbia), Carl Moriarty (Christchurch)
Application Number: 10/564,119
International Classification: A45F 3/08 (20060101); A45F 3/04 (20060101);